People on all U.S. Navy bases on Guam are being advised to boil their water, according to a Navy spokesman.

The notice was issued because of a scheduled water outage from 6 p.m. Friday to 8 a.m. Saturday. Crews were to replace a 12-inch valve in the main water distribution line.

The affected area also includes Polaris Point, Naval Base Guam Fuel Division, Delta Wharf, Echo Wharf, the New Apra housing area and McCool Elementary/Middle School, according to a press release.

Water should be boiled vigorously for one minute. Navy officials said they would let people know when water no longer needs to be boiled.